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Atrial Fibrillation (AF)Phase 2AZALEA-TIMI 71NCT04755283

Safety and Tolerability of Abelacimab (MAA868) vs. Rivaroxaban in Patients With Atrial Fibrillation

A Phase 2 study testing Abelacimab and Rivaroxaban in people with Atrial Fibrillation (AF) and Stroke, run by Anthos Therapeutics, Inc. at 92 sites in 7 countries.

Active, not recruiting

Under way, not looking for participants. Everyone needed has enrolled. The study is still running.

Official record
Search all trials

Trial summary

The purpose of the ANT-006 study is to evaluate the bleeding profile of abelacimab relative to rivaroxaban in patients with atrial fibrillation (AF) at moderate-to-high risk of stroke. Read more about this study

Who is it for?
Ages 55 years and older
Conditions the study is for
Atrial Fibrillation (AF), Stroke
What is being tested?
Abelacimab and Rivaroxaban
Could I receive a placebo?
No, everyone receives an active treatment
How many people
1,287 participants
Where
92 sitesin 7 countries
Study dates
2 Feb 2021to 29 Dec 2028
Phase
Phase 2
Are there results?
Yes, posted in the registrySummary in the doctors' view

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 55 years and older
  • All sexes
  • No healthy volunteers
  • Adult, Older adult

Who may be able to join

  • Male and female patients ≥ 55 years old
  • Patients with a history of atrial fibrillation (AF) or atrial flutter with planned indefinite anticoagulation
  • Patients with a CHA2DS2-VASc of ≥4 OR a CHA2DS2-VASc of ≥3 with at least 1 of the following:
  • Planned concomitant use of antiplatelet medication use (i.e., aspirin and/or P2Y12 inhibitor) for the duration of the trial
  • Creatinine Clearance (CrCl) ≤50 ml/min by the Cockcroft-Gault equation

Who cannot join

  • History of hypersensitivity to any of the study drugs (including rivaroxaban) or its excipients, to drugs of similar chemical classes, or any contraindication listed in the label for rivaroxaban
  • Patients with an intracranial or intraocular bleed within the 3 months prior to screening
  • Clinically significant mitral stenosis (valve area <1.5 cm2)
  • Mechanical heart valve or other indication for anticoagulation therapy other than atrial fibrillation (e.g., venous thromboembolism)
  • Known presence of an atrial myxoma or left ventricular thrombus
  • History of left atrial appendage closure or removal
  • Active endocarditis
  • Other protocol defined Inclusion/Exclusion criteria may apply

Trial locations and contacts

92 sites in 7 countries.

92 sites in 7 countries

United States28 sites

  • Anthos Investigative Site

    Baltimore, Maryland, 21229-5222

  • Anthos Investigative Site

    Camp Hill, Pennsylvania, 17011

  • Anthos Investigative Site

    Clearwater, Florida, 33756

  • Anthos Investigative Site

    Daytona Beach, Florida, 32114-2321

  • Anthos Investigative Site

    Falls Church, Virginia, 22042

  • Anthos Investigative Site

    Fargo, North Dakota, 58104

  • Anthos Investigative Site

    Framingham, Massachusetts, 01701

  • Anthos Investigative Site

    Haverhill, Massachusetts, 01830

  • Anthos Investigative Site

    Huntsville, Alabama, 35801

  • Anthos Investigative Site

    Johns Creek, Georgia, 30024

  • Anthos Investigative Site

    Kingsport, Tennessee, 37660

  • Anthos Investigative Site

    Kingwood, Texas, 77339

  • Anthos Investigative Site

    Lansing, Michigan, 48912

  • Anthos Investigative Site

    Largo, Florida, 33777

  • Anthos Investigative Site

    Lenoir, North Carolina, 28645

  • Anthos Investigative Site

    Manassas, Virginia, 20109

  • Anthos Investigative Site

    Mobile, Alabama, 36608

  • Anthos Investigative Site

    Odessa, Texas, 79761-5133

  • Anthos Investigative Site

    Oklahoma City, Oklahoma, 73135

  • Anthos Investigative Site

    Owensboro, Kentucky, 42303

  • Anthos Investigative Site

    Poughkeepsie, New York, 12601

  • Anthos Investigative Site

    Safety Harbor, Florida, 34695

  • Anthos Investigative Site

    Saint Augustine, Florida, 32086

  • Anthos Investigative Site

    Salisbury, Maryland, 21804

  • Anthos Investigative Site

    Sewell, New Jersey, 08080

  • Anthos Investigative Site

    Southampton, New York, 11968

  • Anthos Investigative Site

    Stamford, Connecticut, 06905

  • Anthos Investigative Site

    Tomball, Texas, 77375

Other trials in United States

Poland18 sites

  • Anthos Investigative Site

    Bielsko-Biala, Silesian Voivodeship, 43-316

  • Anthos Investigative Site

    Chrzanów, Lesser Poland Voivodeship, 32-500

  • Anthos Investigative Site

    Dąbrowa Górnicza, Silesian Voivodeship, 41-300

  • Anthos Investigative Site

    Elblag, Warmian-Masurian Voivodeship, 82-300

  • Anthos Investigative Site

    Gdynia, GDY, 81-423

  • Anthos Investigative Site

    Gdynia, Pomeranian Voivodeship, 81-157

  • Anthos Investigative Site

    Krakow, Lesser Poland Voivodeship, 31-202

  • Anthos Investigative Site

    Lodz, Łódź Voivodeship, 92-213

  • Anthos Investigative Site

    Lublin, Lublin Voivodeship, 20-001

  • Anthos Investigative Site

    Płock, Masovian Voivodeship, 09-402

  • Anthos Investigative Site

    Przemyśl, Podkarpackie Voivodeship, 37-700

  • Anthos Investigative Site

    Ruda Śląska, Silesian Voivodeship, 41-710

  • Anthos Investigative Site

    Tychy, Silesian Voivodeship, 43-100

  • Anthos Investigative Site

    Warsaw, Masovian Voivodeship, 02-097

  • Anthos Investigative Site

    Warsaw, Masovian Voivodeship, 04-628

  • Anthos Investigative Site

    Wroclaw, Lower Silesian Voivodeship, 51-162

  • Anthos Investigative Site

    Zamość, Lubusz Voivodeship, 22-400

  • Anthos Investigative Site

    Żarów, Lower Silesian Voivodeship, 58-130

Other trials in Poland

Czechia15 sites

  • Anthos Investigative Site

    Brandýs nad Labem, Central Bohemia, 250 01

  • Anthos Investigative Site

    Česká Lípa, LI, 470 01

  • Anthos Investigative Site

    Holešov, Zlín, 769 01

  • Anthos Investigative Site

    Kroměříž, ZL, 767 01

  • Anthos Investigative Site

    Liberec, LB, 460 01

  • Anthos Investigative Site

    Liberec, LI, 460 01

  • Anthos Investigative Site

    Mariánské Lázně, KA, 353 01

  • Anthos Investigative Site

    Pardubice, PA, 530 02

  • Anthos Investigative Site

    Poděbrady, Central Bohemia, 29001

  • Anthos Investigative Site

    Prague, PR, 10100

  • Anthos Investigative Site

    Prague, PR, 110 00

  • Anthos Investigative Site

    Prague, PR, 158 00

  • Anthos Investigative Site

    Příbram, Central Bohemia, 261 01

  • Anthos Investigative Site

    Slaný, Central Bohemia, 274 01

  • Anthos Investigative Site

    Trutnov, KR, 541 01

Other trials in Czechia

Hungary13 sites

  • Anthos Investigative Site

    Baja, BK, 6500

  • Anthos Investigative Site

    Balatonfüred, VE, 8230

  • Anthos Investigative Site

    Balatonfüred, VM, 8230

  • Anthos Investigative Site

    Budapest, BP, 1036

  • Anthos Investigative Site

    Budapest, BP, 1122

  • Anthos Investigative Site

    Budapest, BU, 1033

  • Anthos Investigative Site

    Budapest, BU, 1134

  • Anthos Investigative Site

    Debrecen, HB, 4025

  • Anthos Investigative Site

    Kaposvár, SO, 7400

  • Anthos Investigative Site (4002)

    Nyíregyháza, SZ, 4400

  • Anthos Investigative Site (4003)

    Nyíregyháza, SZ, 4400

  • Anthos Investigative Site

    Orosháza, BE, 5900

  • Anthos Investigative Site

    Székesfehérvár, FE, 8000

Other trials in Hungary

Taiwan7 sites

  • Anthos Investigative Site

    Hualien City, HUA, 970

  • Anthos Investigative Site

    Kaohsiung City, KHH, 807

  • Anthos Investigative Site

    Taipei, HSZ, 30071

  • Anthos Investigative Site

    Taipei, TPE, 11217

  • Anthos Investigative Site

    Taipei, TPE, 116

  • Anthos Investigative Site

    Tiachung, TXG, 404

  • Anthos Investigative Site

    Yilan, ILA, 26058

Other trials in Taiwan

South Korea6 sites

  • Anthos Investigative Site

    Seogu, Busan, 49201

  • Anthos Investigative Site

    Seongnam-si, Gyeonggi-do, 13496

  • Anthos Investigative Site

    Seongnam-si, Gyeonggi-do, 13620

  • Anthos Investigative Site

    Seoul, Seoul, 158-710

  • Anthos Investigative Site

    Seoul, Seoul, 3080

  • Anthos Investigative Site

    Seoul, Seoul, 3722

Other trials in South Korea

Canada5 sites

  • Anthos Investigative Site

    Cambridge, Ontario, N1R 7R1

  • Anthos Investigative Site

    Greater Sudbury, Ontario, P3B 4H5

  • Anthos Investigative Site

    Greenfield Park, Quebec, J4V 2G8

  • Anthos Investigative Site

    Montreal, Quebec, H1T 3Y7

  • Anthos Investigative Site

    Oshawa, Ontario, L1J2K1

Other trials in Canada

About this study

Official title: A Multicenter, RandomiZed, Active-ControLled Study to Evaluate the Safety and Tolerability of Two Blinded Doses of Abelacimab (MAA868) Compared With Open-Label Rivaroxaban in Patients With Atrial Fibrillation (AZALEA)

The purpose of the ANT-006 study is to evaluate the bleeding profile of abelacimab relative to rivaroxaban in patients with atrial fibrillation (AF) at moderate-to-high risk of stroke.

Being tested
Abelacimab, Rivaroxaban
Keywords
randomized, prospective, blinded endpoint evaluation, abelacimab, MAA868, rivaroxaban, atrial fibrillation, Factor XI, stroke, bleeding events, anti-coagulant, anticoagulation therapy
Medical subject headings
Atrial Fibrillation, Stroke

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • AbelacimabBiological

    Also called MAA868

    Abelacimab provided as liquid in vial (150 mg/mL)

  • RivaroxabanDrug

    Rivaroxaban 15 mg and 20 mg provided as commercially available film-coated tablets

Study groups in NCT04755283
Study groupRoleWhat they receive
Abelacimab 90 mg (MAA868)ExperimentalTreatment group 1: Abelacimab low dose subcutaneous (s.c.) monthly Extension Treatment Group: Abelacimab high dose subcutaneous (s.c.) monthly
Receives: Biological: Abelacimab
Abelacimab 150 mg (MAA868)ExperimentalTreatment group 2: Abelacimab high dose subcutaneous (s.c.) monthly Extension Treatment Group: Abelacimab high dose subcutaneous (s.c.) monthly
Receives: Biological: Abelacimab
RivaroxabanActive comparatorTreatment group 3: Rivaroxaban 20 mg by mouth; orally (p.o.) once per day with the evening meal Patients with a Creatinine Clearance (CrCl) ≤50 ml/min by the Cockcroft-Gault equation will have a dose adaptation to rivaroxaban 15 mg p.o. daily.
Receives: Drug: Rivaroxaban

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Incidence Rate of the First Occurrence of Composite of International Society on Thrombosis and Haemostasis (ISTH)-Defined Major Bleeding or Clinically Relevant Non-Major (CRNM) Bleeding Events

    The number of participants experiencing the first occurrence of the composite of ISTH-defined major bleeding or CRNM bleeding events divided by the number of 100 person-years through the first event or end of treatment across all participants, is presented. For participants not experiencing events, person-years is calculated through the end of treatment during the randomized phase.

    Measured: Assessed at every visit from randomization through the end of the randomized phase of the study, up to 33 months.

Secondary outcomes (2)

  1. Incidence Rate of the First Occurrence of ISTH-defined Major Bleeding Events

    The number of participants experiencing the first occurrence of ISTH-defined major bleeding events divided by the number of 100 person-years through the first event or end of treatment across all participants, is presented. For participants not experiencing events, person-years is calculated through the end of treatment during the randomized phase.

    Measured: Assessed at every visit from randomization through the end of the randomized phase of the study, up to 33 months.

  2. Incidence Rate of the First Occurrence of ISTH-defined Major or CRNM or Minor Bleeding Events

    The number of participants experiencing the first occurrence of the composite of ISTH-defined major or CRNM or minor bleeding events divided by the number of 100 person-years through the first event or end of treatment across all participants, is presented. For participants not experiencing events, person-years is calculated through the end of treatment during the randomized phase.

    Measured: Assessed at every visit from randomization through the end of the randomized phase of the study, up to 33 months.

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted16 Feb 2021
  2. Study start2 Feb 2021
  3. Primary completion15 Feb 2024
  4. Study completion29 Dec 2028 (estimated)

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase 2
Primary purpose
Supportive care
Allocation
Randomised
Intervention model
Parallel groups
Model description
This is an event-driven, randomized, active-controlled, blinded endpoint, parallel-group study to evaluate the effect of two blinded doses of abelacimab relative to open-label rivaroxaban on the rate of major or clinically relevant non-major (CRNM) bleeding events in patients with atrial fibrillation (AF) who are at moderate-to-high risk of stroke.
Masking
Triple blind
Who is masked
Participant, Care provider, Investigator
Enrolment
1,287 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT04755283
Sponsor's protocol ID
ANT-006
Other IDs
2020-004507-13, CMAA868A2204
Acronym
AZALEA-TIMI 71
Status last verified
Oct 2025
First submitted
11 Feb 2021
Last updated
6 Nov 2025
Data monitoring committee
Yes
FDA-regulated drug
Yes
FDA-regulated device
No
Individual data sharing
Yes: Novartis is committed to sharing with qualified external researchers, access to patient-level data and supporting clinical documents from eligible studies. These requests are reviewed and approved by an independent review panel on the basis of scientific merit. All data provided is anonymized to respect the privacy of patients who have participated in the trial in line with applicable laws and regulations. This trial data availability is according to the criteria and process described on www.clinicalstudydatarequest.com

Publications

  • Ruff CT, Patel SM, Giugliano RP, Morrow DA, Hug B, Kuder JF, Goodrich EL, Chen SA, Goodman SG, Joung B, Kiss RG, Spinar J, Wojakowski W, Weitz JI, Murphy SA, Wiviott SD, Parkar S, Bloomfield D, Sabatine MS; AZALEA-TIMI 71 Investigators. Abelacimab versus Rivaroxaban in Patients with Atrial Fibrillation. N Engl J Med. 2025 Jan 23;392(4):361-371. doi: 10.1056/NEJMoa2406674.

    PubMed 39842011

  • Small AM, Patel SM, Giugliano RP, Morrow DA, Goodrich EL, Hug B, Parkar S, Chen SA, Goodman SG, Joung B, Kiss RG, Wojakowski W, Weitz JI, Bloomfield D, Sabatine MS, Ruff CT. Prior anticoagulation experience and bleeding risk with the factor XI inhibitor abelacimab in AZALEA-TIMI 71. Blood. 2026 May 29:blood.2026033829. doi: 10.1182/blood.2026033829. Online ahead of print.

    PubMed 42213637

  • Al Said S, Patel SM, Giugliano RP, Morrow DA, Goodrich EL, Murphy SA, Hug B, Parkar S, Chen SA, Goodman SG, Joung B, Kiss RG, Wojakowski W, Weitz JI, Bloomfield D, Sabatine MS, Ruff CT. Abelacimab vs Rivaroxaban in Older Individuals With Atrial Fibrillation: A Prespecified Analysis of the Phase 2b AZALEA-TIMI 71 Trial. JAMA Cardiol. 2026 Mar 1;11(3):298-303. doi: 10.1001/jamacardio.2025.5418.

    PubMed 41637102

  • Al Said S, Patel SM, Giugliano RP, Morrow DA, Goodrich EL, Murphy SA, Hug B, Parkar S, Chen SA, Goodman SG, Joung B, Kiss RG, Wojakowski W, Weitz JI, Bloomfield D, Sabatine MS, Ruff CT. Abelacimab Versus Rivaroxaban in Patients With Atrial Fibrillation on Antiplatelet Therapy: A Prespecified Analysis of the AZALEA-TIMI 71 Trial. Circulation. 2025 Aug 5;152(5):290-296. doi: 10.1161/CIRCULATIONAHA.125.074037. Epub 2025 Jun 23.

    PubMed 40546068

Questions about this trial

What is this clinical trial studying?

A Phase 2 study testing Abelacimab and Rivaroxaban in people with Atrial Fibrillation (AF) and Stroke, run by Anthos Therapeutics, Inc. at 92 sites in 7 countries.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 5 inclusion and 8 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: under way, not looking for participants, as of the sponsor's last update on 6 Nov 2025. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 92 sites in United States, Poland, Czechia, Hungary, Taiwan and 2 more countries. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

Yes. Results are posted in the registry (first posted 30 Jul 2025). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Incidence Rate of the First Occurrence of Composite of International Society on Thrombosis and Haemostasis (ISTH)-Defined Major Bleeding or Clinically Relevant Non-Major (CRNM) Bleeding Events (time frame: Assessed at every visit from randomization through the end of the randomized phase of the study, up to 33 months.). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT04755283, which also lists 4 linked publications.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 6 Nov 2025.

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